hostlib/hostLib/a71ch/ex/ex_boot.c - a71ch-crypto-support - Git at Google

 /**
  * @file ex_boot.c
  * @author NXP Semiconductors
  * @version 1.0
  * @par License
  *
  * Copyright 2016,2020 NXP
  * SPDX-License-Identifier: Apache-2.0
  *
  * @par Description
  * Handover of SCP03 session keys from bootloader to OS. Refer to ::exBoot for more details.
  */

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
 #include <inttypes.h>

 #include "a71ch_ex.h"
 #include "a71_debug.h"
 #include "sm_types.h"
 #include "sm_apdu.h"
 #include "tst_sm_util.h"
 #include "tst_a71ch_util.h"
 #include "sm_printf.h"
 #include "axHostCrypto.h"
 #include "tstHostCrypto.h"
 #include "scp.h"
 #include "ax_util.h"
 #include "app_boot.h"

 #if defined(SCI2C)
 #include "sci2c.h"
 #endif

 #if defined(SCI2C)
 static U8 writeStateToFile(char *szFilename, SmCommState_t *commState, Scp03SessionState_t *scp03State);
 static U8 readStateFromFile(char *szFilename, SmCommState_t *commState, Scp03SessionState_t *scp03State);
 #endif

 char* axExBootGetBootModeAsString(U8 bootMode)
 {
     if (bootMode == BOOT_SKIP_EXAMPLE)
     {
         return "Skip boot example";
     }
     else if (bootMode == BOOT_SIMULATED_CYCLE)
     {
         return "Do full boot cycle (Bootloader/OS combined)";
     }
     else if (bootMode == BOOT_BOOTLOADER_ROLE)
     {
         return "Mimick behaviour of bootloader only (store session state on filesystem)";
     }
     else if (bootMode == BOOT_HOST_OS_RESUME)
     {
         return "Mimick behaviour of Host OS only (retrieve session state from filesystem)";
     }
     else
     {
         PRINTF("bootMode not defined\r\n");
         assert(0);
         return "not defined";
     }
 }

 static void signalFunctionCallback(ScpEvent_t event, void *context)
 {
     AX_UNUSED_ARG(context);
     PRINTF("scpCallback: ");
     switch (event)
     {
         case SCP_WRONG_PADDING:
             PRINTF("Wrong padding\r\n");
         break;

         case SCP_WRONG_RESPMAC:
             PRINTF("Wrong response mac\r\n");
         break;

         case SCP_GENERIC_FAILURE:
             PRINTF("Non specified failure\r\n");
         break;

         default:
             PRINTF("Unknown event type\r\n");
         break;
     }
     return;
 }
 /// @endcond

 /**
 * This example illustrates that the HostOS does NOT need to know the SCP03 Base Keys
 * to establish an SCP03 session (provided the boot loader has established the
 * SCP03 session and saved the SCP03 session state)
 *
 * When using SCI2C the bootloader must also save the SCI2C state.
 *
 * - The boot loader
 *       - Sets an initial SCP03 base key set (based on random data retrieved from
 *         the SM (Secure Module))
 *       - Establishes an SCP03 session
 *       - Stores the SCP03 session (optionally also SCI2C state)
 *
 * - The OS
 *       - Retrieves the SCP03 session and communication state
 *       - Resumes the SCP03 session
 *
 * \note When the OS takes over from the boot loader the communication link with
 *    the Secure Element may not be broken.
 * \note Storing the session and communication state on the filesystem is done for convenience
 *    in this example. Use an appropriate and secure sharing mechanism in a product implementation.
 * \note Full functionality of this example is only available when connecting to the A71CH over SCI2C.
 * @param[in] bootMode One of the following values
 *   - ::BOOT_SIMULATED_CYCLE Can be used to simulate handover of session keys (no dependency on link protocol)
 *   - ::BOOT_BOOTLOADER_ROLE Play the role of initial bootloader and store session and communication state to filesystem
 *   - ::BOOT_HOST_OS_RESUME  Play the role of OS and retrieve session and communication state from the filesystem
 */
 U8 exBoot(U8 bootMode)
 {
     U8 result = 1;
     U8 initMode = INIT_MODE_NO_RESET;

     U8 scpKeyEncBase[SCP_KEY_SIZE];
     U8 scpKeyMacBase[SCP_KEY_SIZE];
     U8 scpKeyDekBase[SCP_KEY_SIZE];

     U8 dataRef[] = {0xBE, 0xFA, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07};
     U16 dataRefLen = sizeof(dataRef);
     U8 dataFetch[8];
     U16 packetSize;

     U16 connectStatus;
     U8 Atr[64] = {0};
     U16 AtrLen = sizeof(Atr);

     SmCommState_t commState = {0};
     Scp03SessionState_t sessionState;

     U16 sw = SW_OK;
 #if defined(SCI2C)
     char szFilename[] = "sessionState";
 #endif

     PRINTF("\r\n-----------\r\nStart exBoot(%s)\r\n------------\r\n", axExBootGetBootModeAsString(bootMode));

     if (bootMode == BOOT_SKIP_EXAMPLE)
     {
         PRINTF("***** WARNING: exBoot example is skipped *****\r\n");
     }
     else if (bootMode == BOOT_SIMULATED_CYCLE)
     {
         initMode = INIT_MODE_RESET;

         // Installing Callback (this step is optional)
         SCP_Subscribe(signalFunctionCallback, NULL);
         DEV_ClearChannelState();
 #if defined(SCI2C)|| defined(T1oI2C)
         SM_Close(NULL, SMCOM_CLOSE_MODE_TERMINATE);
 #endif
         connectStatus = SM_Connect(NULL, &commState, Atr, &AtrLen);
         if (connectStatus != SW_OK)
         {
             sm_printf(CONSOLE, "Failed to establish connection to Secure Module: 0x%04" PRIX32 "\r\n", connectStatus);
             result = 0;
             return result;
         }
         else
         {
 #ifndef SMCOM_JRCP_V1
             int i=0;
             sm_printf(CONSOLE, "ATR=0x");
             for (i=0; i<AtrLen; i++) sm_printf(CONSOLE, "%02" PRIX16 ".", Atr[i]);
             sm_printf(CONSOLE, "\r\n");
 #endif
         }

         // STAGE-0:
         // - Force the A71CH into the initial state (only possible when in Debug Mode)
         sm_printf(CONSOLE, "Initialize Module\r\n");
         result &= a71chInitModule(initMode);

         // STAGE-1:
         // - Fetch random data from the A71CH
         // - Set the SCP03 keys based on this random data
         // - This binding between Host and A71CH must only be done once
         result &= axExCreateAndSetInitialHostScpKeys(scpKeyEncBase, scpKeyMacBase, scpKeyDekBase);

         // STAGE-2:
         // - Locally store the SCP03 base keys on the Host (for re-use in the next boot cycle)
         // - Set up the authenticated and encrypted SCP03 channel with the A71CH.
         result &= axExAuthenticate(scpKeyEncBase, scpKeyMacBase, scpKeyDekBase);

         // STAGE-3:
         // - Write an 8 byte pattern to GPStorage (just using some standard A71CH functionality)
         packetSize = dataRefLen;
         PRINTF( "\r\nA71_SetGpData(0, %d, ...)\r\n", packetSize);
         sw = A71_SetGpData(0, dataRef, packetSize);
         result &= AX_CHECK_SW(sw, SW_OK, "A71_SetGpData fails");

         // Before Handing over to the Host OS:
         // - Retrieve and store the SCP03 session state
         // - Retrieve and store SCI2C communication state
         SCP_GetScpSessionState(&sessionState);
         // At this stage the System Integrator must store Session State in Mailbox for HostOS
 #if defined(SCI2C)
         commState.param1 = sci2c_GetSequenceCounter();
         // At this stage the System Integrator must store communication state in Mailbox for HostOS
         SM_Close(NULL, SMCOM_CLOSE_MODE_STD);
 #endif
         sm_printf(DBGOUT, "\r\n\r\n");
         sm_printf(DBGOUT, "******************************************************************\r\n");
         sm_printf(DBGOUT, "** System Integrator must store Communication and Session State **\r\n");
         sm_printf(DBGOUT, "******************************************************************\r\n");

         DEV_ClearChannelState();

         // +++ Handover from Boot to HostOS +++

         // ** Host OS phase **
         SM_ResumeConnection(&commState, &sessionState);

         // - Retrieve and compare the 8 byte reference pattern from GPStorage (just using some standard A71CH functionality)
         packetSize = dataRefLen;
         PRINTF( "\r\nA71_GetGpData(0, %d, ...)\r\n", packetSize);
         sw = A71_GetGpData(0, dataFetch, packetSize);
         result &= AX_CHECK_SW(sw, SW_OK, "A71_GetGpData fails");
         axPrintByteArray ("dataFetch", dataFetch, packetSize, AX_COLON_32);
         result &= AX_COMPARE_BYTE_ARRAY("dataRef", dataRef, dataRefLen,
             "dataFetch", dataFetch, dataRefLen, AX_COLON_32);
     }
 #if defined(SCI2C)
     else if (bootMode == BOOT_BOOTLOADER_ROLE)
     {
         initMode = INIT_MODE_RESET;

         // Installing Callback (this step is optional)
         SCP_Subscribe(signalFunctionCallback, NULL);
         DEV_ClearChannelState();
         SM_Close(NULL, SMCOM_CLOSE_MODE_TERMINATE);
         connectStatus = SM_Connect(NULL, &commState, Atr, &AtrLen);
         if (connectStatus != SW_OK)
         {
             sm_printf(CONSOLE, "Failed to establish connection to Secure Module: 0x%04" PRIX32 "\r\n", connectStatus);
             result = 0;
             return result;
         }
         else
         {
             int i=0;
             sm_printf(CONSOLE, "ATR=0x");
             for (i=0; i<AtrLen; i++) sm_printf(CONSOLE, "%02" PRIX16 ".", Atr[i]);
             sm_printf(CONSOLE, "\r\n");
         }

         // STAGE-0:
         // - Force the A71CH into the initial state (only possible when in Debug Mode)
         sm_printf(CONSOLE, "Initialize Module\r\n");
         result &= a71chInitModule(initMode);

         // STAGE-1:
         // - Fetch random data from the A71CH
         // - Set the SCP03 keys based on this random data
         result &= axExCreateAndSetInitialHostScpKeys(scpKeyEncBase, scpKeyMacBase, scpKeyDekBase);

         // STAGE-2:
         // - Locally store the SCP03 base keys
         // - Set up the authenticated and encrypted SCP03 channel with the A71CH.
         result &= axExAuthenticate(scpKeyEncBase, scpKeyMacBase, scpKeyDekBase);

         // STAGE-3:
         // - Write an 8 byte pattern to GPStorage (just using some standard A71CH functionality)
         packetSize = dataRefLen;
         PRINTF( "\r\nA71_SetGpData(0, %d, ...)\r\n", packetSize);
         sw = A71_SetGpData(0, dataRef, packetSize);
         result &= AX_CHECK_SW(sw, SW_OK, "A71_SetGpData fails");

         // Before Handing over to the Host OS:
         // - Retrieve and store the SCP03 session state
         // - Retrieve and store SCI2C communication state
         SCP_GetScpSessionState(&sessionState);
         commState.param1 = sci2c_GetSequenceCounter();

         SM_Close(NULL, SMCOM_CLOSE_MODE_STD);

         sm_printf(DBGOUT, "\r\n\r\n");
         sm_printf(DBGOUT, "******************************************************************\r\n");
         sm_printf(DBGOUT, "** System Integrator must store Communication and Session State **\r\n");
         sm_printf(DBGOUT, "******************************************************************\r\n");
         sm_printf(DBGOUT, "..\r\n..\r\n");

         // WARNING: Simply writing the SessionState to the file system is not a secure implementation.
         // it must not be used in products.
         writeStateToFile(szFilename, &commState, &sessionState);

         DEV_ClearChannelState();

     }
     else if (bootMode == BOOT_HOST_OS_RESUME)
     {
         SmCommState_t retrCommState;
         Scp03SessionState_t retrScp03State;

         readStateFromFile(szFilename, &retrCommState, &retrScp03State);
         PRINTF("retrCommState.param1         : 0x%02" PRIX16 "\r\n", retrCommState.param1);
         PRINTF("retrCommState.hostLibVersion : 0x%02" PRIX16 "\r\n", retrCommState.hostLibVersion);
         PRINTF("retrCommState.appletVersion  : 0x%04" PRIX32 "\r\n", retrCommState.appletVersion);

         DEV_ClearChannelState();

         // +++ Handover from Boot to HostOS +++

         sm_printf(DBGOUT, "\r\n\r\n");
         sm_printf(DBGOUT, "*******************************************************\r\n");
         sm_printf(DBGOUT, "** Host OS resumes SCP03 session with Secure Element **\r\n");
         sm_printf(DBGOUT, "*******************************************************\r\n");
         // ** Host OS phase **
         SM_ResumeConnection(&retrCommState, &retrScp03State);

         // - Retrieve and compare the 8 byte reference pattern from GPStorage (just using some standard A71CH functionality)
         packetSize = dataRefLen;
         PRINTF( "\r\nA71_GetGpData(0, %d, ...)\r\n", packetSize);
         sw = A71_GetGpData(0, dataFetch, packetSize);
         result &= AX_CHECK_SW(sw, SW_OK, "A71_GetGpData fails");
         axPrintByteArray ("dataFetch", dataFetch, packetSize, AX_COLON_32);

         result &= AX_COMPARE_BYTE_ARRAY("dataRef", dataRef, dataRefLen,
             "dataFetch", dataFetch, dataRefLen, AX_COLON_32);
     }
 #endif // defined(SCI2C)
     else
     {
         PRINTF("bootMode (0x%02" PRIX16 ") is not defined.\r\n", (uint16_t)bootMode);
         result = 0;
     }

     // overall result
     PRINTF("\r\n-----------\r\nEnd exBoot(%s), result = %s\r\n------------\r\n",
         axExBootGetBootModeAsString(bootMode), ((result == 1)? "OK": "FAILED"));

     return result;
 }

 /**
  * The host fetches random data from the A71CH and sets these as SCP03 base keys in the
  * A71CH.
  *
  * @param[in,out] keyEnc IN: Buffer to contain key; OUT: Key created and inserted into A71CH
  * @param[in,out] keyMac IN: Buffer to contain key; OUT: Key created and inserted into A71CH
  * @param[in,out] keyDek IN: Buffer to contain key; OUT: Key created and inserted into A71CH
  */
 U8 axExCreateAndSetInitialHostScpKeys(U8 *keyEnc, U8 *keyMac, U8 *keyDek)
 {
     U8 result = 1;
     U16 err = 0;
     U8 random[3*SCP_KEY_SIZE];
     U8 randomLen = (U8)sizeof(random);
     U8 *currentKeyDek = NULL;
     U8 keyVersion = 1;

     assert(keyEnc != NULL);
     assert(keyMac != NULL);
     assert(keyDek != NULL);

     PRINTF( "\r\n-----------\r\nStart axExCreateAndSetInitialHostScpKeys()\r\n------------\r\n");

     // Security module generates random data for initial SCP03 keys
     sm_printf(CONSOLE, "\r\nA71_GetRandom(randomLen=%d)\r\n", randomLen);
     err = A71_GetRandom(random, randomLen);
     result &= AX_CHECK_SW(err, SW_OK, "err");

     // Storing Static Keys
     memcpy(keyEnc, random, SCP_KEY_SIZE);
     memcpy(keyMac, random + SCP_KEY_SIZE, SCP_KEY_SIZE);
     memcpy(keyDek, random + (2*SCP_KEY_SIZE), SCP_KEY_SIZE);

     keyVersion = (U8) (SST_HOST_SCP_KEYSET >> 8);
     sm_printf(CONSOLE, "\r\nSCP_GP_PutKeys(keyVersion=0x%02" PRIX16 ")\r\n", keyVersion);
     err = SCP_GP_PutKeys(keyVersion, keyEnc, keyMac, keyDek, currentKeyDek, AES_KEY_LEN_nBYTE);
     result &= AX_CHECK_SW(err, SW_OK, "err");

     PRINTF( "\r\n-----------\r\nEnd axExCreateAndSetInitialHostScpKeys(), result = %s\r\n------------\r\n",
         ((result == 1)? "OK": "FAILED"));

     return result;
 }

 /**
  * The host locally stores the SCP03 base keys passed as parameters and establishes
  * the authenticated and encrypted SCP03 channel with the A71CH.
  *
  * @param[in] keyEnc IN: SCP03 base key
  * @param[in] keyMac IN: SCP03 base key
  * @param[in] keyDek IN: SCP03 base key
  */
 U8 axExAuthenticate(U8 *keyEnc, U8 *keyMac, U8 *keyDek)
 {
     U8 sCounter[3];
     U16 sCounterLen = sizeof(sCounter);

     U8 result = 1;
     U16 err = 0;

     PRINTF( "\r\n-----------\r\nStart axExAuthenticate()\r\n------------\r\n");

     // Authenticate Channel
     sm_printf(CONSOLE, "\r\nSCP_Authenticate()\r\n");
     err = SCP_Authenticate(keyEnc, keyMac, keyDek, SCP_KEY_SIZE, sCounter, &sCounterLen);
     result &= AX_CHECK_SW(err, SW_OK, "err");
     result &= AX_CHECK_U16(sCounterLen, 0, "Only expected when SCP03 is configured for pseudo-random challenge");

     PRINTF( "\r\n-----------\r\nEnd axExAuthenticate(), result = %s\r\n------------\r\n",
         ((result == 1)? "OK": "FAILED"));

     return result;
 }

 #if defined(SCI2C)
 static U8 writeStateToFile(char *szFilename, SmCommState_t *commState, Scp03SessionState_t *scp03State)
 {
     U8 result = 1;
 #ifdef FTR_FILE_SYSTEM
     FILE *fHandle = NULL;

     fHandle = fopen(szFilename, "w");

     if (fHandle == NULL)
     {
         sm_printf(DBGOUT, "Failed to open file %s for writing\r\n", szFilename);
         return 0;
     }

     fwrite((const void *) commState, sizeof(SmCommState_t), 1, fHandle);
     fwrite((const void *) scp03State, sizeof(Scp03SessionState_t), 1, fHandle);

     fclose(fHandle);
 #endif
     return result;
 }

 static U8 readStateFromFile(char *szFilename, SmCommState_t *commState, Scp03SessionState_t *scp03State)
 {
     U8 result = 1;
 #ifdef FTR_FILE_SYSTEM
     FILE *fHandle = NULL;

     fHandle = fopen(szFilename, "r");

     if (fHandle == NULL)
     {
         sm_printf(DBGOUT, "Failed to open file %s for reading", szFilename);
         return 0;
     }

     fread((void *) commState, sizeof(SmCommState_t), 1, fHandle);
     fread((void *) scp03State, sizeof(Scp03SessionState_t), 1, fHandle);

     fclose(fHandle);
 #endif
     return result;
 }
 #endif
	/**
	* @file ex_boot.c
	* @author NXP Semiconductors
	* @version 1.0
	* @par License
	*
	* Copyright 2016,2020 NXP
	* SPDX-License-Identifier: Apache-2.0
	*
	* @par Description
	* Handover of SCP03 session keys from bootloader to OS. Refer to ::exBoot for more details.
	*/

	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <assert.h>
	#include <inttypes.h>

	#include "a71ch_ex.h"
	#include "a71_debug.h"
	#include "sm_types.h"
	#include "sm_apdu.h"
	#include "tst_sm_util.h"
	#include "tst_a71ch_util.h"
	#include "sm_printf.h"
	#include "axHostCrypto.h"
	#include "tstHostCrypto.h"
	#include "scp.h"
	#include "ax_util.h"
	#include "app_boot.h"

	#if defined(SCI2C)
	#include "sci2c.h"
	#endif

	#if defined(SCI2C)
	static U8 writeStateToFile(char szFilename, SmCommState_t commState, Scp03SessionState_t *scp03State);
	static U8 readStateFromFile(char szFilename, SmCommState_t commState, Scp03SessionState_t *scp03State);
	#endif

	char* axExBootGetBootModeAsString(U8 bootMode)
	{
	if (bootMode == BOOT_SKIP_EXAMPLE)
	{
	return "Skip boot example";
	}
	else if (bootMode == BOOT_SIMULATED_CYCLE)
	{
	return "Do full boot cycle (Bootloader/OS combined)";
	}
	else if (bootMode == BOOT_BOOTLOADER_ROLE)
	{
	return "Mimick behaviour of bootloader only (store session state on filesystem)";
	}
	else if (bootMode == BOOT_HOST_OS_RESUME)
	{
	return "Mimick behaviour of Host OS only (retrieve session state from filesystem)";
	}
	else
	{
	PRINTF("bootMode not defined\r\n");
	assert(0);
	return "not defined";
	}
	}

	static void signalFunctionCallback(ScpEvent_t event, void *context)
	{
	AX_UNUSED_ARG(context);
	PRINTF("scpCallback: ");
	switch (event)
	{
	case SCP_WRONG_PADDING:
	PRINTF("Wrong padding\r\n");
	break;

	case SCP_WRONG_RESPMAC:
	PRINTF("Wrong response mac\r\n");
	break;

	case SCP_GENERIC_FAILURE:
	PRINTF("Non specified failure\r\n");
	break;

	default:
	PRINTF("Unknown event type\r\n");
	break;
	}
	return;
	}
	/// @endcond

	/**
	* This example illustrates that the HostOS does NOT need to know the SCP03 Base Keys
	* to establish an SCP03 session (provided the boot loader has established the
	* SCP03 session and saved the SCP03 session state)
	*
	* When using SCI2C the bootloader must also save the SCI2C state.
	*
	* - The boot loader
	* - Sets an initial SCP03 base key set (based on random data retrieved from
	* the SM (Secure Module))
	* - Establishes an SCP03 session
	* - Stores the SCP03 session (optionally also SCI2C state)
	*
	* - The OS
	* - Retrieves the SCP03 session and communication state
	* - Resumes the SCP03 session
	*
	* \note When the OS takes over from the boot loader the communication link with
	* the Secure Element may not be broken.
	* \note Storing the session and communication state on the filesystem is done for convenience
	* in this example. Use an appropriate and secure sharing mechanism in a product implementation.
	* \note Full functionality of this example is only available when connecting to the A71CH over SCI2C.
	* @param[in] bootMode One of the following values
	* - ::BOOT_SIMULATED_CYCLE Can be used to simulate handover of session keys (no dependency on link protocol)
	* - ::BOOT_BOOTLOADER_ROLE Play the role of initial bootloader and store session and communication state to filesystem
	* - ::BOOT_HOST_OS_RESUME Play the role of OS and retrieve session and communication state from the filesystem
	*/
	U8 exBoot(U8 bootMode)
	{
	U8 result = 1;
	U8 initMode = INIT_MODE_NO_RESET;

	U8 scpKeyEncBase[SCP_KEY_SIZE];
	U8 scpKeyMacBase[SCP_KEY_SIZE];
	U8 scpKeyDekBase[SCP_KEY_SIZE];

	U8 dataRef[] = {0xBE, 0xFA, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07};
	U16 dataRefLen = sizeof(dataRef);
	U8 dataFetch[8];
	U16 packetSize;

	U16 connectStatus;
	U8 Atr[64] = {0};
	U16 AtrLen = sizeof(Atr);

	SmCommState_t commState = {0};
	Scp03SessionState_t sessionState;

	U16 sw = SW_OK;
	#if defined(SCI2C)
	char szFilename[] = "sessionState";
	#endif

	PRINTF("\r\n-----------\r\nStart exBoot(%s)\r\n------------\r\n", axExBootGetBootModeAsString(bootMode));

	if (bootMode == BOOT_SKIP_EXAMPLE)
	{
	PRINTF("*** WARNING: exBoot example is skipped ***\r\n");
	}
	else if (bootMode == BOOT_SIMULATED_CYCLE)
	{
	initMode = INIT_MODE_RESET;

	// Installing Callback (this step is optional)
	SCP_Subscribe(signalFunctionCallback, NULL);
	DEV_ClearChannelState();
	#if defined(SCI2C)\|\| defined(T1oI2C)
	SM_Close(NULL, SMCOM_CLOSE_MODE_TERMINATE);
	#endif
	connectStatus = SM_Connect(NULL, &commState, Atr, &AtrLen);
	if (connectStatus != SW_OK)
	{
	sm_printf(CONSOLE, "Failed to establish connection to Secure Module: 0x%04" PRIX32 "\r\n", connectStatus);
	result = 0;
	return result;
	}
	else
	{
	#ifndef SMCOM_JRCP_V1
	int i=0;
	sm_printf(CONSOLE, "ATR=0x");
	for (i=0; i<AtrLen; i++) sm_printf(CONSOLE, "%02" PRIX16 ".", Atr[i]);
	sm_printf(CONSOLE, "\r\n");
	#endif
	}

	// STAGE-0:
	// - Force the A71CH into the initial state (only possible when in Debug Mode)
	sm_printf(CONSOLE, "Initialize Module\r\n");
	result &= a71chInitModule(initMode);

	// STAGE-1:
	// - Fetch random data from the A71CH
	// - Set the SCP03 keys based on this random data
	// - This binding between Host and A71CH must only be done once
	result &= axExCreateAndSetInitialHostScpKeys(scpKeyEncBase, scpKeyMacBase, scpKeyDekBase);

	// STAGE-2:
	// - Locally store the SCP03 base keys on the Host (for re-use in the next boot cycle)
	// - Set up the authenticated and encrypted SCP03 channel with the A71CH.
	result &= axExAuthenticate(scpKeyEncBase, scpKeyMacBase, scpKeyDekBase);

	// STAGE-3:
	// - Write an 8 byte pattern to GPStorage (just using some standard A71CH functionality)
	packetSize = dataRefLen;
	PRINTF( "\r\nA71_SetGpData(0, %d, ...)\r\n", packetSize);
	sw = A71_SetGpData(0, dataRef, packetSize);
	result &= AX_CHECK_SW(sw, SW_OK, "A71_SetGpData fails");

	// Before Handing over to the Host OS:
	// - Retrieve and store the SCP03 session state
	// - Retrieve and store SCI2C communication state
	SCP_GetScpSessionState(&sessionState);
	// At this stage the System Integrator must store Session State in Mailbox for HostOS
	#if defined(SCI2C)
	commState.param1 = sci2c_GetSequenceCounter();
	// At this stage the System Integrator must store communication state in Mailbox for HostOS
	SM_Close(NULL, SMCOM_CLOSE_MODE_STD);
	#endif
	sm_printf(DBGOUT, "\r\n\r\n");
	sm_printf(DBGOUT, "******************************************************************\r\n");
	sm_printf(DBGOUT, " System Integrator must store Communication and Session State \r\n");
	sm_printf(DBGOUT, "******************************************************************\r\n");

	DEV_ClearChannelState();

	// +++ Handover from Boot to HostOS +++

	// Host OS phase
	SM_ResumeConnection(&commState, &sessionState);

	// - Retrieve and compare the 8 byte reference pattern from GPStorage (just using some standard A71CH functionality)
	packetSize = dataRefLen;
	PRINTF( "\r\nA71_GetGpData(0, %d, ...)\r\n", packetSize);
	sw = A71_GetGpData(0, dataFetch, packetSize);
	result &= AX_CHECK_SW(sw, SW_OK, "A71_GetGpData fails");
	axPrintByteArray ("dataFetch", dataFetch, packetSize, AX_COLON_32);
	result &= AX_COMPARE_BYTE_ARRAY("dataRef", dataRef, dataRefLen,
	"dataFetch", dataFetch, dataRefLen, AX_COLON_32);
	}
	#if defined(SCI2C)
	else if (bootMode == BOOT_BOOTLOADER_ROLE)
	{
	initMode = INIT_MODE_RESET;

	// Installing Callback (this step is optional)
	SCP_Subscribe(signalFunctionCallback, NULL);
	DEV_ClearChannelState();
	SM_Close(NULL, SMCOM_CLOSE_MODE_TERMINATE);
	connectStatus = SM_Connect(NULL, &commState, Atr, &AtrLen);
	if (connectStatus != SW_OK)
	{
	sm_printf(CONSOLE, "Failed to establish connection to Secure Module: 0x%04" PRIX32 "\r\n", connectStatus);
	result = 0;
	return result;
	}
	else
	{
	int i=0;
	sm_printf(CONSOLE, "ATR=0x");
	for (i=0; i<AtrLen; i++) sm_printf(CONSOLE, "%02" PRIX16 ".", Atr[i]);
	sm_printf(CONSOLE, "\r\n");
	}

	// STAGE-0:
	// - Force the A71CH into the initial state (only possible when in Debug Mode)
	sm_printf(CONSOLE, "Initialize Module\r\n");
	result &= a71chInitModule(initMode);

	// STAGE-1:
	// - Fetch random data from the A71CH
	// - Set the SCP03 keys based on this random data
	result &= axExCreateAndSetInitialHostScpKeys(scpKeyEncBase, scpKeyMacBase, scpKeyDekBase);

	// STAGE-2:
	// - Locally store the SCP03 base keys
	// - Set up the authenticated and encrypted SCP03 channel with the A71CH.
	result &= axExAuthenticate(scpKeyEncBase, scpKeyMacBase, scpKeyDekBase);

	// STAGE-3:
	// - Write an 8 byte pattern to GPStorage (just using some standard A71CH functionality)
	packetSize = dataRefLen;
	PRINTF( "\r\nA71_SetGpData(0, %d, ...)\r\n", packetSize);
	sw = A71_SetGpData(0, dataRef, packetSize);
	result &= AX_CHECK_SW(sw, SW_OK, "A71_SetGpData fails");

	// Before Handing over to the Host OS:
	// - Retrieve and store the SCP03 session state
	// - Retrieve and store SCI2C communication state
	SCP_GetScpSessionState(&sessionState);
	commState.param1 = sci2c_GetSequenceCounter();

	SM_Close(NULL, SMCOM_CLOSE_MODE_STD);

	sm_printf(DBGOUT, "\r\n\r\n");
	sm_printf(DBGOUT, "******************************************************************\r\n");
	sm_printf(DBGOUT, " System Integrator must store Communication and Session State \r\n");
	sm_printf(DBGOUT, "******************************************************************\r\n");
	sm_printf(DBGOUT, "..\r\n..\r\n");

	// WARNING: Simply writing the SessionState to the file system is not a secure implementation.
	// it must not be used in products.
	writeStateToFile(szFilename, &commState, &sessionState);

	DEV_ClearChannelState();

	}
	else if (bootMode == BOOT_HOST_OS_RESUME)
	{
	SmCommState_t retrCommState;
	Scp03SessionState_t retrScp03State;

	readStateFromFile(szFilename, &retrCommState, &retrScp03State);
	PRINTF("retrCommState.param1 : 0x%02" PRIX16 "\r\n", retrCommState.param1);
	PRINTF("retrCommState.hostLibVersion : 0x%02" PRIX16 "\r\n", retrCommState.hostLibVersion);
	PRINTF("retrCommState.appletVersion : 0x%04" PRIX32 "\r\n", retrCommState.appletVersion);

	DEV_ClearChannelState();

	// +++ Handover from Boot to HostOS +++

	sm_printf(DBGOUT, "\r\n\r\n");
	sm_printf(DBGOUT, "*******************************************************\r\n");
	sm_printf(DBGOUT, " Host OS resumes SCP03 session with Secure Element \r\n");
	sm_printf(DBGOUT, "*******************************************************\r\n");
	// Host OS phase
	SM_ResumeConnection(&retrCommState, &retrScp03State);

	// - Retrieve and compare the 8 byte reference pattern from GPStorage (just using some standard A71CH functionality)
	packetSize = dataRefLen;
	PRINTF( "\r\nA71_GetGpData(0, %d, ...)\r\n", packetSize);
	sw = A71_GetGpData(0, dataFetch, packetSize);
	result &= AX_CHECK_SW(sw, SW_OK, "A71_GetGpData fails");
	axPrintByteArray ("dataFetch", dataFetch, packetSize, AX_COLON_32);

	result &= AX_COMPARE_BYTE_ARRAY("dataRef", dataRef, dataRefLen,
	"dataFetch", dataFetch, dataRefLen, AX_COLON_32);
	}
	#endif // defined(SCI2C)
	else
	{
	PRINTF("bootMode (0x%02" PRIX16 ") is not defined.\r\n", (uint16_t)bootMode);
	result = 0;
	}

	// overall result
	PRINTF("\r\n-----------\r\nEnd exBoot(%s), result = %s\r\n------------\r\n",
	axExBootGetBootModeAsString(bootMode), ((result == 1)? "OK": "FAILED"));

	return result;
	}

	/**
	* The host fetches random data from the A71CH and sets these as SCP03 base keys in the
	* A71CH.
	*
	* @param[in,out] keyEnc IN: Buffer to contain key; OUT: Key created and inserted into A71CH
	* @param[in,out] keyMac IN: Buffer to contain key; OUT: Key created and inserted into A71CH
	* @param[in,out] keyDek IN: Buffer to contain key; OUT: Key created and inserted into A71CH
	*/
	U8 axExCreateAndSetInitialHostScpKeys(U8 keyEnc, U8 keyMac, U8 *keyDek)
	{
	U8 result = 1;
	U16 err = 0;
	U8 random[3*SCP_KEY_SIZE];
	U8 randomLen = (U8)sizeof(random);
	U8 *currentKeyDek = NULL;
	U8 keyVersion = 1;

	assert(keyEnc != NULL);
	assert(keyMac != NULL);
	assert(keyDek != NULL);

	PRINTF( "\r\n-----------\r\nStart axExCreateAndSetInitialHostScpKeys()\r\n------------\r\n");

	// Security module generates random data for initial SCP03 keys
	sm_printf(CONSOLE, "\r\nA71_GetRandom(randomLen=%d)\r\n", randomLen);
	err = A71_GetRandom(random, randomLen);
	result &= AX_CHECK_SW(err, SW_OK, "err");

	// Storing Static Keys
	memcpy(keyEnc, random, SCP_KEY_SIZE);
	memcpy(keyMac, random + SCP_KEY_SIZE, SCP_KEY_SIZE);
	memcpy(keyDek, random + (2*SCP_KEY_SIZE), SCP_KEY_SIZE);

	keyVersion = (U8) (SST_HOST_SCP_KEYSET >> 8);
	sm_printf(CONSOLE, "\r\nSCP_GP_PutKeys(keyVersion=0x%02" PRIX16 ")\r\n", keyVersion);
	err = SCP_GP_PutKeys(keyVersion, keyEnc, keyMac, keyDek, currentKeyDek, AES_KEY_LEN_nBYTE);
	result &= AX_CHECK_SW(err, SW_OK, "err");

	PRINTF( "\r\n-----------\r\nEnd axExCreateAndSetInitialHostScpKeys(), result = %s\r\n------------\r\n",
	((result == 1)? "OK": "FAILED"));

	return result;
	}

	/**
	* The host locally stores the SCP03 base keys passed as parameters and establishes
	* the authenticated and encrypted SCP03 channel with the A71CH.
	*
	* @param[in] keyEnc IN: SCP03 base key
	* @param[in] keyMac IN: SCP03 base key
	* @param[in] keyDek IN: SCP03 base key
	*/
	U8 axExAuthenticate(U8 keyEnc, U8 keyMac, U8 *keyDek)
	{
	U8 sCounter[3];
	U16 sCounterLen = sizeof(sCounter);

	U8 result = 1;
	U16 err = 0;

	PRINTF( "\r\n-----------\r\nStart axExAuthenticate()\r\n------------\r\n");

	// Authenticate Channel
	sm_printf(CONSOLE, "\r\nSCP_Authenticate()\r\n");
	err = SCP_Authenticate(keyEnc, keyMac, keyDek, SCP_KEY_SIZE, sCounter, &sCounterLen);
	result &= AX_CHECK_SW(err, SW_OK, "err");
	result &= AX_CHECK_U16(sCounterLen, 0, "Only expected when SCP03 is configured for pseudo-random challenge");

	PRINTF( "\r\n-----------\r\nEnd axExAuthenticate(), result = %s\r\n------------\r\n",
	((result == 1)? "OK": "FAILED"));

	return result;
	}

	#if defined(SCI2C)
	static U8 writeStateToFile(char szFilename, SmCommState_t commState, Scp03SessionState_t *scp03State)
	{
	U8 result = 1;
	#ifdef FTR_FILE_SYSTEM
	FILE *fHandle = NULL;

	fHandle = fopen(szFilename, "w");

	if (fHandle == NULL)
	{
	sm_printf(DBGOUT, "Failed to open file %s for writing\r\n", szFilename);
	return 0;
	}

	fwrite((const void *) commState, sizeof(SmCommState_t), 1, fHandle);
	fwrite((const void *) scp03State, sizeof(Scp03SessionState_t), 1, fHandle);

	fclose(fHandle);
	#endif
	return result;
	}

	static U8 readStateFromFile(char szFilename, SmCommState_t commState, Scp03SessionState_t *scp03State)
	{
	U8 result = 1;
	#ifdef FTR_FILE_SYSTEM
	FILE *fHandle = NULL;

	fHandle = fopen(szFilename, "r");

	if (fHandle == NULL)
	{
	sm_printf(DBGOUT, "Failed to open file %s for reading", szFilename);
	return 0;
	}

	fread((void *) commState, sizeof(SmCommState_t), 1, fHandle);
	fread((void *) scp03State, sizeof(Scp03SessionState_t), 1, fHandle);

	fclose(fHandle);
	#endif
	return result;
	}
	#endif